Retaining device for an improved contact

ABSTRACT

The invention relates to a retaining device for maintaining an electric contact ( 24 ) in the connector socket ( 22 ) of a connection box ( 20 ). The inventive device comprises a bearing surface ( 50 ) interacting with a shoulder ( 52 ) which is arranged on the level of said contact ( 24 ) and is characterised in that the bearing surface and the shoulder ( 52 ) are provided with supplementary nonplanar profiles in such a way that the thus obtained contact plane has a larger contact surface than the contact planes having the equal size across the width thereof.

FIELD OF THE INVENTION

The present invention relates to a retaining device for maintainingcontact in the form of a flexible arm that can hold a contact, notably afemale cage contact, in a socket of a connection box.

BACKGROUND OF THE INVENTION

Connection boxes bearing retaining devices for maintaining contact,which can receive electric contacts, are described in applications U.S.Pat. No. 5,746,624, U.S. Pat. No. 6,068,512, U.S. Pat. No. 5,190,476 andU.S. Pat. No. 5,836,796.

According to the different embodiments, a connection box generallycomprises a first part in which sockets are arranged and possibly asecond part in the form of a frontal grid.

An electric contact, for example such as described in patent applicationFR-2,818,027, can come to be housed in these sockets.

Each socket generally comprises an elastic element provided with abearing surface cooperating with a shoulder created at the level of theelectric contact. Thus, in its rest position, the bearing surface of theelastic element is supported against the shoulder and is opposite thecontact outlet. The elastic element is sufficiently flexible andcomprises an appropriately designed surface, joined to the bearingsurface to permit its flattening during introduction of the electriccontact.

The electric contact can have different shapes, notably a parallelepipedbody, the shoulder being created at the level of an opening provided atthe level of the surfaces or formed directly by a part of the rearsurface of said body.

In FIGS. 1A and 1B, elastic elements 10 of a connection box are shown indetail, each of them having a bearing surface 12 that can cooperate witha shoulder 14 of an electric contact 16.

According to the different embodiments, the bearing surface and theshoulder have planar surfaces. These planar surfaces assure an absorbingof axial forces but not shearing force. Moreover, there is always someplay between the contact and the socket, so that this play combined withthe non-absorbing of shearing forces can generate a rapid deteriorationof the retaining device.

Document U.S. Pat. No. 4,969,841 proposes an improved retaining devicecomprising three different bearing surfaces that cooperate with ashoulder and two wings created at the level of the electric contact.Even though this device obtains a better absorption of forces than thedevices previously mentioned, it is not entirely satisfactory since itrequires a relatively complex form of the elastic element and aparticular form of the electric contact, having two wings that projectrelative to the body.

The present invention also seeks to alleviate the disadvantages of theprior art by proposing an improved retaining device for maintaining anelectric contact in a connection box, of simple design, obtaining abetter absorption of both axial and shearing forces.

SUMMARY OF THE INVENTION

For this purpose, the subject of this invention is a retaining devicethat can maintain an electric contact in a connection box socket, saiddevice comprising a bearing surface that can cooperate with a shouldercreated at the level of said contact, characterized in that the bearingsurface and the shoulder have complementary nonplanar profiles, so as toobtain a contact surface greater than that obtained by planar surfaceshaving the same width dimension.

According to a preferred form of embodiment, the bearing surfacecomprises at least one projecting profile, for example in the form of aprojection with slightly inclined lateral walls, arranged in roughlysymmetrical manner.

The invention also proposes an electric contact designed for saidretaining device.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics and inventions will arise from the descriptionthat follows of the invention, a description given solely by way ofexample, with regard to the attached drawings in which:

FIGS. 1A and 1B are perspective views illustrating an electric contactand a retaining device of the prior art,

FIGS. 2A and 2B are perspective views illustrating an electric contactand a retaining device according to the invention,

FIG. 3 is a perspective view illustrating the complementary surfaces ofan electric contact and a retaining device,

FIG. 4 is a perspective sectional view illustrating a connection box inwhich an electric contact is inserted, held by a retaining device; and

FIG. 5 is a sectional view in a direction parallel to the electriccontact illustrating a connection box into which a first electriccontact is inserted, and a second electric contact is shown ready to beinserted.

DETAILED DESCRIPTION OF THE INVENTION

In FIGS. 4 and 5, a connection box 20 is shown, comprising one or moresockets 22 into each of which an electric contact 24 can be inserted.

Electric contact 24 can have different shapes, notably such as describedin patent application FR-2,818,027. It generally comprises a body 28,preferably of parallelepiped shape, one part of which can constitute anelectric contact zone properly speaking, as well as a rear zone 30assuring the connection between an electrical cable 32 and said body 28in the form of a crimping, for example.

The structure of the electric contact is not shown in more detailbecause it is not the essential element of the present invention and iswithin the scope of the person skilled in the art.

An example of connection box 20 is shown in detail in FIG. 5. Itcomprises a first part 34 or block in which one or more sockets 22 arearranged opening up on either side of block 34, positioned in one ormore rows, and a second part 36, called grid, that can be embedded inthe block and covers one of the faces of the block at the level of whichthe sockets emerge, an element in the form of a gasket 38 assuring atight seal with a skirt of a complementary connector. This grid 36comprises openings 40 positioned at the level of each socket permittingpassage of an element that can be connected with the correspondingelectric contact of the box.

Each socket 22 has a section more or less adapted to electric contact 24and comprises a lug 42 positioned more or less at the level of one endopening up close to the grid, able to immobilize electric contact 24 intranslation along a first direction, as well as a retaining device 44 inthe form of an elastic element permitting the introduction of theelectric contact in its socket and immobilizing said contact intranslation along a second direction once inserted.

This retaining device 44 is present in the form of a flexible blade 46connected to box 20, extending in a roughly parallel manner and spacedat a distance to one of the socket surfaces so as to be deformable andto permit the introduction of the electric contact.

This flexible blade 46, sometimes called a locking tongue, comprises aramp 48 at the level of the face opposite the electric contact, in thedirection of introduction of said contact, which is terminated by abearing surface 50 roughly perpendicular to the principal axis of saidblade.

Ramp 48 permits the deformation of blade 46 during introduction ofelectric contact 24 while bearing surface 50 can cooperate with ashoulder 52 provided at the level of the electric contact and thus canimmobilize said contact 24.

Advantageously, bearing surface 50 is far from distal end 54 of blade 46so as to facilitate unlocking of the retaining device.

Shoulder 52 provided at the level of the contact can be made up by theedge of an opening created in body 28 of the electric contact or, asshown by the different figures, by the rear surface 56 of the body or bya part of this surface.

According to the invention, bearing surface 50 and shoulder 52 havecomplementary, non-planar profiles, so as to obtain a contact surfacesuperior to that obtained by planar surfaces having the same widthdimension. These profiles are advantageously interlocking profilesoriented along an axis parallel to the axis of insertion of the contactinto the socket.

According to one embodiment, the bearing surface or shoulder comprises aprofile including a projection 58, positioned preferably in asymmetrical manner, with slightly inclined lateral walls 60, the othersurface having a complementary profile.

By way of comparison, the planar bearing surface of the prior art,illustrated by FIG. 1B has a surface of 0.63 mm², while the bearingsurface of the invention, illustrated by FIG. 2B has a surface of 0.88mm² for the same width dimension, which corresponds to an increase of40% of the contact surface.

This increase of the contact surface permits either reducing the contactpressure for the same stresses, or increasing the admissible stressesfor the same contact pressure, which confers improved mechanicalcharacteristics upon the retaining device according to the inventionwhen compared with devices of the prior art.

Moreover, the nonplanar shape, preferably incorporating at least oneprojecting profile, permits absorbing both axial and shearing forces.

This projecting shape notably oriented along the principal axis of theblade or of the contact also permits a better immobilization intranslation in the transversal direction even when play is presentbetween the electric contact and the socket.

Of course, the invention is clearly not limited to the embodiment shownand described above, but on the contrary covers all the variants,notably with regard to the shapes of the connection box and the electriccontact as well as the complementary profiles of the bearing surface andof the shoulder.

1. A retaining device that can maintain an electric contact in a socketof a connection box, said device comprising a bearing surface that cancooperate with a shoulder of said contact, wherein the bearing surfaceand the shoulder have complementary nonplanar profiles with a contactsurface formed at a junction between the bearing surface and theshoulder that is greater than that obtained by planar surfaces having asame width dimension, characterized in that the complementary profilesare interlocking profiles oriented along an axis parallel to the axis ofinsertion of the contact into the socket.
 2. The retaining deviceaccording to claim 1, further characterized in that bearing surfacecomprises at least one projecting profile.
 3. The device according toclaim 2, further characterized in that bearing surface comprises aprojection with slightly inclined lateral walls, positioned roughlysymmetrically.
 4. An electric contact that can be immobilized in asocket of a connection box by means of a retaining device according toclaim 1 comprising a bearing surface that can cooperate with a shouldercreated at the level of said contact, such that shoulder and bearingsurface have complementary, nonplanar profiles, so as to obtain agreater contact surface than that obtained by planar surfaces having thesame width dimension, characterized in that the complementary profilesare interlocking profiles oriented along an axis parallel to theinsertion axis of the contact in the socket.
 5. The electric contactaccording to claim 4, further characterized in that shoulder comprisesat least one projecting profile.
 6. The electric contact according toclaim 5, further characterized in that shoulder comprises a projectionwith slightly inclined lateral walls, positioned in a roughlysymmetrical manner.
 7. The electric contact according to claim 6,further characterized in that shoulder comprises at least one hollowprofile.
 8. A system for retaining an electric contact in a connectionbox comprising: the connection box comprising a retaining member with anonplanar bearing surface; and the electric contact comprising anonplanar shoulder contacted by the nonplanar bearing surface, whereinthe nonplanar shoulder and the nonplanar bearing surface each compriseinclined lateral walls which cooperate to form a wedging contact betweenthe nonplanar bearing surface and the nonplanar shoulder.
 9. A system asin claim 8 wherein the retaining member comprises a deflectable blade.10. A system as in claim 9 wherein a distal end of the blade extends infront of the nonplanar bearing surface.
 11. A system as in claim 8wherein the nonplanar bearing surf ace comprises a projection.
 12. Asystem as in claim 8 wherein the nonplanar shoulder comprises a recess.13. A system as in claim 8 wherein the nonplanar bearing surface and thenonplanar shoulder have complementary mating shapes.
 14. A system forretaining an electric contact in a connection box comprising: theconnection box comprising a retaining member with a nonplanar bearingsurface; and the electric contact comprising a nonplanar shouldercontacted by the nonplanar bearing surface, wherein the nonplanarshoulder and the nonplanar bearing surface have complementary shapeswith a projection section extending into a recess section to form awedging contact between the bearing surface and the shoulder, andwherein the nonplanar bearing surface comprises the projection sectionand the nonplanar shoulder comprises the recess section.
 15. A system asin claim 14 wherein the projection section comprises at least oneinclined lateral wall and the recess section comprises at least onemating inclined lateral wall.